Prefer binary realloc to self-managed buffers

Use erlang's allocator and simplify the code by writing into the
buffer we're going to give back anyway.

Also introduce a function to NUL-terminate iolist buffers, which can
avoid memory copying.

c_src/commit.c

@@ -40,7 +40,6 @@ geef_commit_tree(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 	term_obj = enif_make_resource(env, obj);
 	enif_release_resource(obj);
 
-
 	return enif_make_tuple3(env, atoms.ok, atoms.tree, term_obj);
 
 }

c_src/geef.c

@@ -123,6 +123,16 @@ geef_oom(ErlNifEnv *env)
 	return enif_make_tuple2(env, atoms.error, atoms.enomem);
 }
 
+int geef_terminate_binary(ErlNifBinary *bin)
+{
+	if (!enif_realloc_binary(bin, bin->size + 1))
+		return 0;
+
+	bin->data[bin->size - 1] = '\0';
+
+	return 1;
+}
+
 static ErlNifFunc geef_funcs[] =
 {
 	{"repository_init", 2, geef_repository_init},

c_src/geef.h

@@ -29,4 +29,7 @@ typedef struct {
 
 extern geef_atoms atoms;
 
+/** NUL-terminate a binary */
+int geef_terminate_binary(ErlNifBinary *bin);
+
 #endif

c_src/reference.c

@@ -49,7 +49,6 @@ geef_reference_lookup(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 	git_reference *ref;
 	ErlNifBinary bin;
 	ERL_NIF_TERM term_ref;
-	char *name;
 	int error;
 
 	if (!enif_get_resource(env, argv[0], geef_repository_type, (void **) &repo))
@@ -58,15 +57,10 @@ geef_reference_lookup(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 	if (!enif_inspect_iolist_as_binary(env, argv[1], &bin))
 		return enif_make_badarg(env);
 
-	name = malloc(bin.size + 1);
+	if (!geef_terminate_binary(&bin))
-	if (!name)
 		return geef_oom(env);
 
-	memcpy(name, bin.data, bin.size);
+	error = git_reference_lookup(&ref, repo->repo, (char *)bin.data);
-	name[bin.size] = '\0';
-
-	error = git_reference_lookup(&ref, repo->repo, name);
-	free(name);
 
 	if (error < 0)
 		return geef_error(env);
@@ -128,7 +122,6 @@ static int append_to_list(const char *name, void *payload)
 ERL_NIF_TERM
 geef_reference_glob(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 {
-	char *glob;
 	int error;
 	geef_repository *repo;
 	ErlNifBinary bin;
@@ -140,18 +133,13 @@ geef_reference_glob(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 	if (!enif_inspect_iolist_as_binary(env, argv[1], &bin))
 		return enif_make_badarg(env);
 
-	glob = malloc(bin.size + 1);
+	if (!geef_terminate_binary(&bin))
-	if (!glob)
 		return geef_oom(env);
 
-	memcpy(glob, bin.data, bin.size);
-	glob[bin.size] = '\0';
-
 	data.env = env;
 	data.list = enif_make_list(env, 0);
 
-	error = git_reference_foreach_glob(repo->repo, glob, GIT_REF_LISTALL, append_to_list, &data);
+	error = git_reference_foreach_glob(repo->repo, (char *) bin.data, GIT_REF_LISTALL, append_to_list, &data);
-	free(glob);
 
 	if (error < 0)
 		return geef_error(env);
@@ -195,7 +183,6 @@ geef_reference_to_id(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 {
 	geef_repository *repo;
 	ErlNifBinary bin;
-	char *name;
 	git_oid id;
 
 	if (!enif_get_resource(env, argv[0], geef_repository_type, (void **) &repo))
@@ -204,14 +191,10 @@ geef_reference_to_id(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 	if (!enif_inspect_iolist_as_binary(env, argv[1], &bin))
 		return enif_make_badarg(env);
 
-	name = malloc(bin.size + 1);
+	if (!geef_terminate_binary(&bin))
-	if (!name)
 		return geef_oom(env);
 
-	memcpy(name, bin.data, bin.size);
+	if (git_reference_name_to_id(&id, repo->repo, (char *)bin.data) < 0)
-	name[bin.size] = '\0';
-
-	if (git_reference_name_to_id(&id, repo->repo, name) < 0)
 		return geef_error(env);
 
 	if (geef_oid_bin(&bin, &id) < 0)

c_src/repository.c

@@ -20,8 +20,7 @@ void geef_odb_free(ErlNifEnv *env, void *cd)
 ERL_NIF_TERM
 geef_repository_init(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 {
-	char *path;
+	int bare;
-	int error, bare;
 	git_repository *repo;
 	geef_repository *res_repo;
 	ErlNifBinary bin;
@@ -30,19 +29,12 @@ geef_repository_init(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 	if (!enif_inspect_iolist_as_binary(env, argv[0], &bin))
 		return enif_make_badarg(env);
 
-	path = malloc(bin.size + 1);
+	if (!geef_terminate_binary(&bin))
-	if (!path)
 		return geef_oom(env);
 
-	memcpy(path, bin.data, bin.size);
-	path[bin.size] = '\0';
-
 	bare = !enif_compare(argv[1], atoms.true);
 
-	error = git_repository_init(&repo, path, bare);
+	if (git_repository_init(&repo, (char *) bin.data, bare) < 0)
-	free(path);
-
-	if (error < 0)
 		return geef_error(env);
 
 	res_repo = enif_alloc_resource(geef_repository_type, sizeof(geef_repository));
@@ -56,8 +48,6 @@ geef_repository_init(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 ERL_NIF_TERM
 geef_repository_open(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 {
-	char *path;
-	int error;
 	git_repository *repo;
 	geef_repository *res_repo;
 	ErlNifBinary bin;
@@ -66,17 +56,10 @@ geef_repository_open(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 	if (!enif_inspect_iolist_as_binary(env, argv[0], &bin))
 		return enif_make_badarg(env);
 
-	path = malloc(bin.size + 1);
+	if (!geef_terminate_binary(&bin))
-	if (!path)
 		return geef_oom(env);
 
-	memcpy(path, bin.data, bin.size);
+	if (git_repository_open(&repo, (char *) bin.data) < 0)
-	path[bin.size] = '\0';
-
-	error = git_repository_open(&repo, path);
-	free(path);
-
-	if (error < 0)
 		return geef_error(env);
 
 	res_repo = enif_alloc_resource(geef_repository_type, sizeof(geef_repository));
@@ -90,57 +73,31 @@ geef_repository_open(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 ERL_NIF_TERM
 geef_repository_discover(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 {
-	char *path, *buffer;
+	ErlNifBinary bin, path;
-	size_t buffer_len;
-	ErlNifBinary bin, res_bin;
 	int error;
 
 	if (!enif_inspect_iolist_as_binary(env, argv[0], &bin))
 		return enif_make_badarg(env);
 
-	path = malloc(bin.size + 1);
+	if (!geef_terminate_binary(&bin))
-	if (!path)
 		return geef_oom(env);
 
-	memcpy(path, bin.data, bin.size);
+	if (!enif_alloc_binary(256, &path))
-	path[bin.size] = '\0';
-
-	buffer_len = 256;
-	buffer = malloc(buffer_len);
-	if (!buffer)
 		return geef_oom(env);
 
-	while ((error = git_repository_discover(buffer, buffer_len, path, 0, NULL)) < 0 &&
+	while ((error = git_repository_discover((char *) path.data, path.size,(char *) bin.data, 0, NULL)) < 0 &&
 	       giterr_last()->klass == GITERR_REPOSITORY) {
-		char *tmp;
+		if (!enif_realloc_binary(&path, path.size * 2))
-		buffer_len *= 2;
-		tmp = realloc(buffer, buffer_len);
-		if (!tmp) {
-			free(path);
-			free(buffer);
 			return geef_oom(env);
-		}
-
-		buffer = tmp;
 	}
 
-	free(path);
-
 	if (error < 0) {
-		free(buffer);
 		return geef_error(env);
 	}
 
-	buffer_len = strlen(buffer);
+	enif_realloc_binary(&path, strlen((char *) path.data));
-	if (!enif_alloc_binary(buffer_len, &res_bin)) {
-		free(buffer);
-		return geef_oom(env);
-	}
 
-	memcpy(res_bin.data, buffer, buffer_len);
+	return enif_make_tuple2(env, atoms.ok, enif_make_binary(env, &path));
-	free(buffer);
-
-	return enif_make_tuple2(env, atoms.ok, enif_make_binary(env, &res_bin));
 }
 
 ERL_NIF_TERM

c_src/tree.c

@@ -40,7 +40,6 @@ static ERL_NIF_TERM tree_entry_to_term(ErlNifEnv *env, const git_tree_entry *ent
 ERL_NIF_TERM
 geef_tree_bypath(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 {
-	char *path;
 	int error;
 	geef_object *obj;
 	ErlNifBinary bin;
@@ -52,17 +51,10 @@ geef_tree_bypath(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 	if (!enif_inspect_iolist_as_binary(env, argv[1], &bin))
 		return enif_make_badarg(env);
 
-	path = malloc(bin.size + 1);
+	if (!geef_terminate_binary(&bin))
-	if (!path)
 		return geef_oom(env);
 
-	memcpy(path, bin.data, bin.size);
+	if (git_tree_entry_bypath(&entry, (git_tree *)obj->obj, (char *) bin.data) < 0)
-	path[bin.size] = '\0';
-
-	error = git_tree_entry_bypath(&entry, (git_tree *)obj->obj, path);
-	free(path);
-
-	if (error < 0)
 		return geef_error(env);
 
 	return tree_entry_to_term(env, entry);